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What MacBook model do you have (System Profiler will help you find out)?

That "eject" sound is the optical drive checking itself and looking for any media which might be inserted into it.

Normally that should only occur during start up or waking from sleep (there is a firmware fix for this), but not during use, unless you slap the MB a bit harder on the side of the SuperDrive - my iBook worked that way.

Since when does that sound occur?
 
Sounds like your CD drive is about to go. Do you have an apple care? If so you might need to take a trip to your nearest store.... If you don't it's really easy to replace yourself if your good with tools.
 
i don't understand. i hardly ever use the cd drive. in the 3 years i have had this computer i have probably only used it 10 times.

You got to remember that it's a computer things go bad... Very time you reboot or put it to sleep it checks to see it there is anything in the drive..
 
Have you tried putting an (expendable) CD back in there and re-ejecting it? If something's gone "out of whack", that may help to get everything back to normal.
 
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